code: def export_positive_infinity_only() -> None:
      node = onnx.helper.make_node(
          "IsInf", inputs=["x"], outputs=["y"], detect_negative=0
      )
  
      x = np.array(
          [-1.7, np.nan, np.inf, 3.6, np.NINF, np.inf], dtype=np.float32
      )
      y = np.isposinf(x)
      expect(node, inputs=[x], outputs=[y], name="test_isinf_positive")
  
file_path: onnx/onnx/backend/test/case/node/isinf.py
imports: import numpy
  import onnx
  from onnx.backend.test.case.base import Base
  from onnx.backend.test.case.node import expect
label_desc: Use image node_id 2 for calling the IsInf obj's underlying member method code with example usage: obj.export_positive_infinity_only() without return types